tpm: Allow reporting the internal state

It is useful to read information about the current TPM state, where
supported, e.g. for debugging purposes when verified boot fails.

Add support for this to the TPM interface as well as Cr50. Add a simple
sandbox test.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

8 files changed, 101 insertions, 0 deletions

diff --git a/cmd/tpm-common.c b/cmd/tpm-common.c
index 47adaffd18..d0c63cadf4 100644
--- a/cmd/tpm-common.c
+++ b/cmd/tpm-common.c
@@ -333,6 +333,26 @@ int do_tpm_info(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	return 0;
 }
 
+int do_tpm_report_state(struct cmd_tbl *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	struct udevice *dev;
+	char buf[80];
+	int rc;
+
+	rc = get_tpm(&dev);
+	if (rc)
+		return rc;
+	rc = tpm_report_state(dev, buf, sizeof(buf));
+	if (rc < 0) {
+		printf("Couldn't get TPM state (%d)\n", rc);
+		return CMD_RET_FAILURE;
+	}
+	printf("%s\n", buf);
+
+	return 0;
+}
+
 int do_tpm_init(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
 	struct udevice *dev;
diff --git a/cmd/tpm-user-utils.h b/cmd/tpm-user-utils.h
index 358ddff576..de4a934aab 100644
--- a/cmd/tpm-user-utils.h
+++ b/cmd/tpm-user-utils.h
@@ -21,6 +21,8 @@ int do_tpm_device(struct cmd_tbl *cmdtp, int flag, int argc,
 		  char *const argv[]);
 int do_tpm_init(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
 int do_tpm_info(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
+int do_tpm_report_state(struct cmd_tbl *cmdtp, int flag, int argc,
+			char *const argv[]);
 int do_tpm(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
 
 #endif /* __TPM_USER_UTILS_H */
diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 4ea5f9f094..d93b83ada9 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -359,6 +359,7 @@ static int do_tpm_pcr_setauthvalue(struct cmd_tbl *cmdtp, int flag,
 static struct cmd_tbl tpm2_commands[] = {
 	U_BOOT_CMD_MKENT(device, 0, 1, do_tpm_device, "", ""),
 	U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
+	U_BOOT_CMD_MKENT(state, 0, 1, do_tpm_report_state, "", ""),
 	U_BOOT_CMD_MKENT(init, 0, 1, do_tpm_init, "", ""),
 	U_BOOT_CMD_MKENT(startup, 0, 1, do_tpm2_startup, "", ""),
 	U_BOOT_CMD_MKENT(self_test, 0, 1, do_tpm2_self_test, "", ""),
@@ -389,6 +390,8 @@ U_BOOT_CMD(tpm2, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
 "    Show all devices or set the specified device\n"
 "info\n"
 "    Show information about the TPM.\n"
+"state\n"
+"    Show internal state from the TPM (if available)\n"
 "init\n"
 "    Initialize the software stack. Always the first command to issue.\n"
 "startup <mode>\n"
diff --git a/drivers/tpm/tpm-uclass.c b/drivers/tpm/tpm-uclass.c
index 0eb35f50c4..5ff0cd3958 100644
--- a/drivers/tpm/tpm-uclass.c
+++ b/drivers/tpm/tpm-uclass.c
@@ -49,6 +49,16 @@ int tpm_get_desc(struct udevice *dev, char *buf, int size)
 	return ops->get_desc(dev, buf, size);
 }
 
+int tpm_report_state(struct udevice *dev, char *buf, int size)
+{
+	struct tpm_ops *ops = tpm_get_ops(dev);
+
+	if (!ops->report_state)
+		return -ENOSYS;
+
+	return ops->report_state(dev, buf, size);
+}
+
 /* Returns max number of milliseconds to wait */
 static ulong tpm_tis_i2c_calc_ordinal_duration(struct tpm_chip_priv *priv,
 					       u32 ordinal)
diff --git a/drivers/tpm/tpm2_tis_sandbox.c b/drivers/tpm/tpm2_tis_sandbox.c
index c26f5d35ab..dd94bdc31f 100644
--- a/drivers/tpm/tpm2_tis_sandbox.c
+++ b/drivers/tpm/tpm2_tis_sandbox.c
@@ -795,6 +795,16 @@ static int sandbox_tpm2_get_desc(struct udevice *dev, char *buf, int size)
 	return snprintf(buf, size, "Sandbox TPM2.x");
 }
 
+static int sandbox_tpm2_report_state(struct udevice *dev, char *buf, int size)
+{
+	struct sandbox_tpm2 *priv = dev_get_priv(dev);
+
+	if (size < 40)
+		return -ENOSPC;
+
+	return snprintf(buf, size, "init_done=%d", priv->init_done);
+}
+
 static int sandbox_tpm2_open(struct udevice *dev)
 {
 	struct sandbox_tpm2 *tpm = dev_get_priv(dev);
@@ -834,6 +844,7 @@ static const struct tpm_ops sandbox_tpm2_ops = {
 	.open		= sandbox_tpm2_open,
 	.close		= sandbox_tpm2_close,
 	.get_desc	= sandbox_tpm2_get_desc,
+	.report_state	= sandbox_tpm2_report_state,
 	.xfer		= sandbox_tpm2_xfer,
 };
 
diff --git a/include/tpm-common.h b/include/tpm-common.h
index a28629e701..b2c5404430 100644
--- a/include/tpm-common.h
+++ b/include/tpm-common.h
@@ -120,6 +120,16 @@ struct tpm_ops {
 	int (*get_desc)(struct udevice *dev, char *buf, int size);
 
 	/**
+	 * report_state() - Collect information about the current TPM state
+	 *
+	 * @dev:	Device to check
+	 * @buf:	Buffer to put the string
+	 * @size:	Maximum size of buffer
+	 * Return: return code of the operation (0 = success)
+	 */
+	int (*report_state)(struct udevice *dev, char *buf, int size);
+
+	/**
 	 * send() - send data to the TPM
 	 *
 	 * @dev:	Device to talk to
@@ -235,6 +245,16 @@ u32 tpm_clear_and_reenable(struct udevice *dev);
 int tpm_get_desc(struct udevice *dev, char *buf, int size);
 
 /**
+ * tpm_report_state() - Collect information about the current TPM state
+ *
+ * @dev:	Device to check
+ * @buf:	Buffer to put the string
+ * @size:	Maximum size of buffer
+ * Return: return code of the operation (0 = success)
+ */
+int tpm_report_state(struct udevice *dev, char *buf, int size);
+
+/**
  * tpm_xfer() - send data to the TPM and get response
  *
  * This first uses the device's send() method to send the bytes. Then it calls
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 52fe178a82..7543df8823 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -107,6 +107,7 @@ obj-$(CONFIG_SYSINFO_GPIO) += sysinfo-gpio.o
 obj-$(CONFIG_UT_DM) += tag.o
 obj-$(CONFIG_TEE) += tee.o
 obj-$(CONFIG_TIMER) += timer.o
+obj-$(CONFIG_TPM_V2) += tpm.o
 obj-$(CONFIG_DM_USB) += usb.o
 obj-$(CONFIG_DM_VIDEO) += video.o
 ifeq ($(CONFIG_VIRTIO_SANDBOX),y)
diff --git a/test/dm/tpm.c b/test/dm/tpm.c
new file mode 100644
index 0000000000..0b46f79959
--- /dev/null
+++ b/test/dm/tpm.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <tpm_api.h>
+#include <dm/test.h>
+#include <test/test.h>
+#include <test/ut.h>
+
+/* Basic test of the TPM uclass */
+static int dm_test_tpm(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+	char buf[50];
+
+	/* check probe success */
+	ut_assertok(uclass_first_device_err(UCLASS_TPM, &dev));
+	ut_assert(tpm_is_v2(dev));
+
+	ut_assert(tpm_report_state(dev, buf, sizeof(buf)));
+	ut_asserteq_str("init_done=0", buf);
+
+	ut_assertok(tpm_init(dev));
+
+	ut_assert(tpm_report_state(dev, buf, sizeof(buf)));
+	ut_asserteq_str("init_done=1", buf);
+
+	return 0;
+}
+DM_TEST(dm_test_tpm, UT_TESTF_SCAN_FDT);